Apparatus for positioning and stabbing pipe in a drilling rig derrick

ABSTRACT

A remotely controlled apparatus for positioning and stabbing pipe within a drilling rig derrick is provided. A support base assembly is mounted to a structural member of a drilling rig derrick. A jointed articulating boom having a boom base member and a boom arm member is attached to the support base assembly and can be pivoted about vertical and horizontal axes. The jointed articulating boom extends and retracts by cooperative motion between the boom base member and the boom arm member. A pipe gripper assembly having opposing arcuate jaws is mounted at the outer extent of the jointed articulating boom and can be pivoted about a horizontal axis. A remote control panel subassembly is used to control the movement of jointed articulating boom and pipe gripper assembly.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] This invention relates to an apparatus for positioning and stabbing tubular goods, including large diameter pipe such as casing, within a drilling rig derrick. More particularly, the present invention pertains to an apparatus which can be mounted within a drilling rig derrick, and which can grip a section of pipe, such as large diameter casing, suspended within said derrick. More particularly still, the present invention pertains to a remotely operated apparatus which can grip a section of pipe suspended within a drilling rig derrick and align such pipe so that threads at the lower end thereof can be joined with mating threads of a section of pipe situated therebelow.

[0003] 2. Brief Description of the Prior Art

[0004] Standard rotary drilling rigs are typically comprised of a supportive rig floor, a roughly vertical derrick extending above said rig floor, and a traveling block which can be raised and lowered within said derrick. Such rig equipment is often used to insert and remove tubular goods, such as pipe, from a wellbore which is being drilled or serviced.

[0005] Drill bits and other equipment used in connection with the drilling and/or servicing of wells are typically conveyed into and out of such wells on tubular pipe known as drill pipe or “drill string”. At a point that a well has been drilled to a desired depth, large diameter pipe called casing is often installed in said well and cemented in place. Such casing, which provides structural integrity to the wellbore and helps keep geologic formations isolated from one another, is also installed in wells using the above described drilling rig equipment.

[0006] Casing, drill pipe or other similar tubular goods are typically installed in wells in a number of different sections of roughly equal length. These sections, often called “joints,” are typically screwed together or otherwise joined end-to-end at the earth's surface in order to form a roughly continuous “string” of pipe. As the bottom or distal end of the pipe string penetrates further into a well, additional joints of pipe are added to the ever lengthening pipe string in the rig derrick. Conversely, when pipe is being removed from a wellbore, the pipe string is pulled from the well and joints are unscrewed in the rig derrick, one or more at a time, until all of the pipe has been retrieved from said well.

[0007] The process of inserting a string of pipe in a well is typically commenced by lowering a first section of pipe into a wellbore at the rig floor, and suspending said section of pipe in place using a set of “lower slips.” In this position, the uppermost end of said first section of pipe is generally situated a few feet above the rig floor. Thereafter, a second section of pipe is lifted within the drilling rig derrick and suspended vertically in said derrick from the rig's traveling block. This second section of pipe is then positioned in linear alignment above the first section of pipe which was previously run into the well. The lower end of said second section is then connected to the upper end of said first section. Once joined, the two sections of pipe are lowered further into the well and hung in place using lower slips. This process is repeated until the desired length of pipe is run into the well.

[0008] In many cases, individual sections of pipe are joined together using threaded connections. In such instances, the upper end of one section of pipe has threads which engage with mating threads on the lower end of an adjacent section of pipe. It is the custom of the oil and gas industry to insert sections of pipe into a wellbore so that male or “pin” end threaded connections face downward, while female or “box” end connections face upward. Thus, when individual joints of pipe are added to a string of pipe in a well in the manner described above, the pin end of the upper joint of pipe (which is suspended within a derrick) is typically “stabbed” into the box end of the lower joint (which is suspended in the well bore). The upper joint is then rotated so that the mating threads of the two joints join together.

[0009] Numerous devices have been developed to assist in the alignment and interconnection of joints of elongated pipe and other tubular goods used in the drilling and completion of oil and gas wells. Many of these devices employ means for gripping a joint of pipe while it is suspended within a derrick. Force is then applied to said suspended pipe joint until it is oriented in linear alignment with one or more joints of pipe which have already been inserted in such wellbore.

[0010] Because drill pipe usually has a smaller diameter than casing, it is often much lighter on a per-foot basis than casing. As a result, a suspended section of drill pipe can generally be manually aligned within a derrick by roughnecks and/or other rig workers. Perhaps more significantly, drill pipe threads are typically very coarse compared to casing threads. Accordingly, drill pipe threads are relatively difficult to misalign when joints of drill pipe are brought into end-to-end abutting relationship for threaded interconnection.

[0011] By contrast, because casing is generally much heavier than drill pipe and other similar tubular goods, it is often difficult, if not impossible, for rig workers to manually position such casing within a derrick. Furthermore, casing joints typically employ connections having relatively fine threads. As a result, it is critical that joints of casing which are to be threadably connected must be in close linear alignment with one another. If not, the threaded pin end of one casing joint can become cross threaded with the box end of the next adjacent casing joint. Such cross-threading can occur even when there is very slight misalignment between two adjacent joints of casing.

[0012] Thus, it is generally advantageous to provide means for positioning heavy tubular goods, such as casing, while it is suspended within a drilling rig derrick. Moreover, such positioning means must promote relatively precise alignment of adjacent joints of casing to ensure proper threaded connection of such casing.

[0013] A number of existing patents disclose systems for racking and positioning of pipe. U.S. Pat. No. 4,077,025 to Callegari et al discloses an apparatus which can be mounted in a drilling rig derrick in order to manipulate and maneuver joints or lengths of drill pipe into or out of one or more slotted fingerboards which are mounted in a derrick. The apparatus includes a pipe manipulating arm which can move in two planes of movement, but cannot be repositioned so that it does not represent an obstruction within the derrick. The device is used solely for the racking of drill pipe of relatively small diameter, and would not be useful for stabbing and manipulating large diameter casing.

[0014] U.S. Pat. No. 3,840,120 to Swoboda et al describes a racking arm which is intended to be mounted on the floor of a drilling rig and used for racking drill pipe, drill collars and riser pipe. The device described in Swoboda cannot be used for stabbing casing from an elevated location above the rig floor in the derrick, especially large diameter casing. The racking arm disclosed in Swoboda also cannot be operated from a remote location so as to control the movement of drill pipe being gripped by said device.

[0015] U.S. Pat. No. 2,615,681 to True describes an apparatus for handling drill pipe to facilitate the coupling and uncoupling of sections of drill pipe used within a wellbore. The apparatus described in True is not well adapted for engaging and positioning sections of pipe having large diameters such as casing. Furthermore, the True apparatus does not allow for of its boom to pivot about a vertical axis to achieve side-to-side motion.

[0016] U.S. Pat. No. 2,450,934 to Calhoun describes an apparatus used for the connection and disconnection of sections of drill pipe as said pipe is inserted into and out of a wellbore. Tongs are mounted on a post extending vertically upward. A control head facilitates operation of said tongs from a remote location. A hydraulically actuated arm is mounted on the supporting post, and its movement is controlled from a remote location. The apparatus described in Calhoun contains numerous limitations not present with the invention described herein.

[0017] U.S. Pat. No. 3,467,262 to Reed discloses a pipe stabbing apparatus utilizing an extensible boom which can be extended and retracted. Said boom may be pivoted in a horizontal plane to enable a stabbing head to reach various positions on the rig. A hydraulic piston and cylinder assembly is used to vary the angular position of the extensible boom on its foundation. Said pipe stabbing head positioned at the end of the boom carries a jaw which is mechanically actuated to open and close the jaw about a section of drill pipe. However, the Reed patent does not provide for the spinning or turning of a suspended section of casing or other pipe within the jaw once it has been gripped.

[0018] U.S. Pat. No. 3,112,830 to Podlesak discloses a pole-handling device which includes an elongated extensible boom which is pivotally connected to a large support structure. A hydraulic cylinder is provided for elevating and lowering the boom, and a set of jaws are carried on the free end of the boom. Such jaws are clamped about the pole by means of a hydraulic piston and cylinder arrangement which permits said jaws to pivot. Due to the size of the support structure upon which the boom and associated hydraulics are carried, the apparatus described in Podlesak is unsuitable for use in stabbing tubular goods suspended within a drilling rig derrick. Moreover, the apparatus described in the Podlesak patent does not permit a sufficient range of motion to adequately position or align such a suspended section of pipe.

[0019] Other stabbing devices for engaging and positioning tubular elements such as drill pipe and casing are set forth in U.S. Pat. Nos. 2,822,024; 2,820,783 and 3,467,262. Additionally, U.S. Pat. No. 2,206,184 to Graham et al discloses an apparatus which can be mounted in the derrick of a drilling rig to center and steady a section of casing or pipe suspended within a drilling rig derrick. The apparatus includes a supporting carriage which is mounted in the derrick. A guiding and steadying member provides a V-shaped surface which can engage a suspended section of casing or pipe. However, the device disclosed in the Graham patent does not provide for actual gripping of a section of pipe. Further, the range of motion of the apparatus disclosed in Graham is very limited.

[0020] A similar device is shown in U.S. Pat. No. 3,533,516. However, the portion of the apparatus which engages a suspended section of casing or pipe section is integrally formed with an elongated arm which can pivot about a horizontal axis, thereby permitting the arm to be yawed or swivelled in a horizontal plane. The arm and the hydraulic piston and cylinder assembly used for imparting the yawing motion are mounted on an upright stand or standard, which in turn is supported on a base plate which can be rested on the rig floor or drilling platform. The apparatus disclosed in the '516 patent contains a number of significant limitations not found in the present invention.

[0021] U.S. Pat. Nos. 4,652,195; 4,921,386; 5,049,020 and 5,062,756 disclose pipe stabbing systems employing a telescoping boom which can be attached to a drilling rig derrick. The free end of said telescoping boom employs pipe grabbing jaws. However, unlike the present invention, the pipe stabbing systems disclosed in the referenced patents permit a limited range of motion for such booms. Further, the pipe grabbing jaws must be adjusted or reconfigured in order to accommodate pipe having diameters outside of certain ranges.

[0022] Thus, there is a need for a pipe stabbing apparatus which can be mounted within a drilling rig derrick, and which can be used to grip and position a section of pipe suspended within such derrick. Specifically, there is a need for a pipe stabbing apparatus having a versatile range of motion in multiple planes of movement. There is further a need for a pipe stabbing apparatus capable of gripping different sizes of pipe having a wide range of different diameters, without having to shut down operations in order to manually adjust or reconfigure such stabbing apparatus.

BRIEF DESCRIPTION OF THE PRESENT INVENTION

[0023] The present invention is a pipe stabbing apparatus which can be easily lifted into a drilling rig derrick and secured to one or more members of such derrick. The apparatus of the present invention is fully automated, and can be remotely controlled from a control panel that can be positioned at virtually any desired location on a rig, including the rig floor. By virtue of such adjustable remote control panel, an operator of the apparatus can position himself so as to view a pipe section which is engaged by the apparatus. Using such direct visual input, an operator can control the movement of the apparatus in order to manipulate the positioning of a first joint of pipe which is suspended in a derrick as it is brought into linear alignment with a second section of pipe suspended within a wellbore.

[0024] The present invention is significantly less bulky than other known devices utilized for this purpose. The apparatus of the present invention employs a jointed boom which can be mounted at virtually any location within a derrick, and thus affords little interference with other operations taking place within said derrick. The apparatus is movable in virtually every plane of motion, and the boom can be easily extended or retracted in order to grip and position a section of pipe suspended from a traveling block in a derrick. The present invention can even grip a suspended section of pipe below the vertical position at which said boom is mounted within said derrick. Moreover, the apparatus of the present invention is especially well adapted for gripping many different sizes of pipe, including very large diameter casing, without requiring operations to cease for adjustment or reconfiguration of the apparatus.

[0025] The pipe stabbing apparatus of the present invention includes a jointed, extensible boom. One end of said boom can be quickly secured to a structural member or cross beam of a drilling rig derrick using a bracket assembly or other similar mechanism. Further, the end of the boom which is secured to the derrick can pivot about both vertical and horizontal axes. A pipe gripper is attached to the opposite (free) end of said extensible boom.

[0026] A primary remote control panel serves as the distribution point or manifold from which hydraulic fluid can be directed to one or more hydraulic piston and cylinder assemblies used to move the boom in several different planes of movement, and to open and/or close said pipe gripper. Said primary remote control panel includes a plurality of solenoid-type valves which can be selectively opened in order to direct such hydraulic fluid and, ultimately, to control movement of the extensible boom and pipe gripper. A secondary remote control panel is also included, in close proximity to said extensible boom, to facilitate manipulation of said boom during the mounting process.

[0027] The primary remote control panel includes lines which can extend to the derrick floor or other desired location on the rig. Certain of these lines are hydraulic lines which function, respectively, to deliver power fluid from a pump to the hydraulic cylinders of the extensible boom mounted in the derrick, and to return such hydraulic fluid to a reservoir. One or more power source cables also extend from the derrick-mounted boom to the electrically operated valves. Additionally, a control cable runs to the primary remote control panel which is positioned at a desired location on the rig which, in most cases, is on the rig floor.

[0028] A secondary control panel is located in relatively close proximity with the jointed extensible boom of the present invention. The secondary control panel is particularly useful when the casing stabber of the present invention is being mounted within a drilling rig derrick, or when said casing stabber is being removed from said derrick. Said jointed extensible boom can be extended and/or retracted as desired in order to facilitate handling and mounting/removal of said casing stabber.

[0029] The jointed, extensible boom can be hydraulically actuated to extend and retract as desired. The end of the boom which is mounted to the derrick can pivot about vertical and horizontal axes, thereby permitting both side-to-side as well as up-and-down movement. A pipe gripper is mounted to the outer or “free” end of said boom. The pipe gripper is comprised of a pair of opposing arcuate jaws that are pivotally supported on the free end of the boom and are hydraulically actuated for opening or closing. Such jaws can be engaged around many different sizes of pipe, and do not impair or restrict the ability of a gripped pipe joint to be rotated or turned about its longitudinal axis. Such opposing arcuate jaws can also be pivoted about a horizontal axis.

[0030] An important object of the present invention is to provide a pipe stabbing apparatus which can be easily taken apart to facilitate transport, storage and operative mounting of the entire apparatus at a selected position within a drilling rig derrick and above the rig floor.

[0031] A further object of the invention is to provide a pipe stabbing apparatus which includes an extensible boom, as well as a pipe gripping assembly at one end, which is hydraulically movable in several planes of motion.

[0032] A further object of the invention is to provide a pipe stabbing apparatus which can grip and steer tubular goods, including large diameter pipe such as casing, and which allows such pipe to be spun or rotated about its longitudinal axis, even while such pipe is engaged by said pipe stabbing apparatus.

[0033] A further object of the present invention is to provide a pipe stabbing apparatus utilizing pipe gripping jaws which can permit many different sizes of pipe to be gripped and moved without the need to adjust or re-size such pipe gripping jaws.

[0034] Additional objects and advantages of the invention will become apparent as the following detailed description of the invention is read in conjunction with the accompanying drawings which illustrate a preferred embodiment of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

[0035]FIG. 1 is a perspective view depicting the pipe stabbing apparatus of the present invention mounted within the derrick of a drilling rig and used for gripping, engaging and aligning a section of casing suspended from a traveling block within said derrick.

[0036]FIG. 2 is a perspective view of the pipe stabbing apparatus of the present invention gripping a section of large diameter casing.

[0037]FIG. 3 is a perspective view of the opposing arcuate pipe gripping jaws of the present invention in the open position.

[0038]FIG. 4 is a perspective view of the opposing arcuate pipe gripping jaws of the present invention in the closed position.

[0039]FIG. 5 is a systemic view of the pipe stabbing apparatus of the present invention wherein the pipe gripping jaws are gripping a section of large diameter casing.

[0040]FIG. 6 is a perspective view of the pipe gripping jaws of the present invention, in the closed position, gripping a section of large diameter casing.

[0041]FIG. 7 is a side view of the pipe gripping jaws of the present invention, in the closed position, gripping a section of large diameter casing.

DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT OF THE INVENTION

[0042] Referring initially to FIG. 1 of the drawings, drilling rig 10 is depicted during operations for the installation of casing into a well. Vertically extending derrick 11 and rig floor 12 are supported on drilling platform 13. Rotary 14, which is positioned on rig floor 12 at the surface of well 15, supports, by means of suitable lower slips 16, an elongated section of casing 17. The upper portion of casing section 17 protrudes out of rotary 14 and is situated above rig floor 12, while the remainder of casing section 17 projects downwardly from the rig floor and, ultimately, into the well 15 being drilled or serviced.

[0043] When installing casing into well 15, it is necessary to serially interconnect multiple sections of casing at a point of joinder a short distance above rig floor 12. The process is commenced by installing a first section of casing 17 into well 15, and hanging or suspending same in place using lower slips 16. As succeeding sections of casing are added to the casing string being installed, the entire string is lowered into well 15 and suspended in place using lower slips 16. This process is repeated until a desired length of casing is installed into wellbore 15.

[0044] Still referring to FIG. 1, casing section 18 is shown suspended from upper slips 19 attached to traveling block 20. Traveling block 20 is capable of vertical movement within derrick 11. Once casing section 18 is placed in linear alignment with casing section 17, roughneck 21 can turn or rotate said casing section 18, thereby causing mating threaded connections at the uppermost end of casing section 17 and the lowermost end of casing section 18 to interconnect.

[0045] The present invention is primarily used to guide or position a suspended first section of large diameter pipe into linear alignment with a second section of pipe in order to facilitate threaded interconnection of said first and second sections of pipe. Referring to FIG. 1, the pipe stabbing apparatus of the present invention, denoted generally as 100, is used to move suspended casing section 18 so as to more precisely align said suspended casing section 18, and more particularly the lowermost threaded end thereof, with the uppermost threaded end of casing section 17, which is suspended in wellbore 15. By aligning said casing sections 17 and 18, said pipe sections can be threadably connected with less chance of cross-threading.

[0046] Still referring to FIG. 1, pipe stabbing apparatus 100 of the present invention is mounted within vertical drilling rig derrick 11. The specific placement of pipe stabbing apparatus 100 within derrick 11 is generally dictated by the layout of the particular drilling rig and derrick on which it is employed. However, said pipe stabbing apparatus 100 is generally mounted at a vertical level which permits maximum functionality and range of motion with respect to sections of pipe suspended within derrick 11, such as casing section 18. Further, while pipe stabbing apparatus 100 can be mounted on any side of derrick 11, said pipe stabbing apparatus 100 is typically positioned so as to permit maximum visibility for personnel located on rig floor 12, and to avoid interference with operation of other equipment within derrick 11.

[0047]FIG. 2 depicts a side perspective view of pipe stabbing apparatus 100 of the present invention. Said pipe stabbing apparatus 100 is mounted to derrick 11 using brackets or similar devices so that said pipe stabbing apparatus projects generally in the direction of well 15 as illustrated in FIG. 1. Depending on the configuration of the particular drilling rig being used, the optimum position for mounting of pipe stabbing apparatus 100 is frequently in direct lateral alignment with the centerline of casing section 18, and near the mid-point of one side of derrick 11.

[0048] Still referring to FIG. 2, pipe stabbing apparatus 100 includes jointed, articulating boom 110. Jointed articulating boom 110 is comprised of boom base member 111 and boom arm member 112, which are pivotably joined with one another using boom pivot joint 113. In the preferred embodiment, said articulating boom is comprised of two structural members, with a single joint therebetween. However, it can be envisioned that other combinations of structural members and pivoting joints could be employed to yield similar results and/or functionality. Also in the preferred embodiment, boom base member 111 includes obtuse angle 111 a, while arm member 112 is substantially straight.

[0049] Jointed articulating boom 110 is attached to base assembly 114, which is used to mount pipe stabbing apparatus 100 to structural members of derrick 11. Although mounting of pipe stabbing apparatus 100 within derrick 11 can be accomplished any number of ways, in the preferred embodiment base assembly is attached to vertical runners 114 a and 114 b. Said vertical runners 114 a and 114 b are in turn bracketed to horizontal cross members or other structural components of rig derrick 11.

[0050] Boom base member 111 is attached to eccentric base plate 119, which is in turn pivotably anchored to vertical base shaft 115. Eccentric base plate 119 rotates about pivot pin 116, thereby permitting boom base member 111 (and thus all of jointed articulating boom 110) to rotate about a vertical axis passing through vertical base shaft 115 and pivot pin 116. In the preferred embodiment of the invention, the range of motion of said eccentric base plate 119 and jointed articulating boom is roughly 180 degrees.

[0051] Rotation of boom base member 110 about pivot pin 116 is powered by hydraulic cylinder 117. One end of hydraulic cylinder 117 is anchored to base assembly 114 with anchor means 118, such as a suitable pin and bracket. Hydraulic cylinder 117 further includes piston rod 120 (substantially obscured from view in FIG. 2). One end of said piston rod 120 is anchored to eccentric plate 119. As piston rod 120 of hydraulic cylinder 117 is extended and retracted, eccentric plate 119 is made to rotate about pivot pin 116, which in turn causes boom base member 111 (and, ultimately, all of jointed articulating boom 110) to rotate about said pivot pin 116.

[0052] Jointed articulating boom 110 extends and retracts by cooperative motion between boom base member 111 and boom arm member 112. Boom base member 111 is pivotably mounted to eccentric plate 119 using horizontal pivot pin 121. As a result, boom base member 111 can pivot about a horizontal axis passing through said horizontal pivot pin 121, thereby permitting boom base member 111 to tilt forward. As such, when mounted within derrick 11, jointed articulating boom can tilt forward in the general direction of well 15.

[0053] The movement of boom base member 111 about the horizontal axis passing through pivot pin 121 is powered by hydraulic cylinder 122. One end of hydraulic cylinder 122 is anchored to vertical base shaft 115. Anchor bracket 123 is pinned to anchor plate 124 by means of a suitable anchor pin 125. Hydraulic cylinder 122 further includes piston rod 126, which can be extended and retracted with respect to hydraulic cylinder 122. The outer end of piston rod 126 is anchored to clevis plate 127 using clevis bracket 128 and clevis pin 129. The movement of piston rod 126 is controlled from a remote control panel subassembly, hereinafter explained, through hydraulic lines or conduits to said hydraulic cylinder and to other hydraulic cylinders used in the casing stabbing apparatus of the invention, and hereinafter described.

[0054] Similarly, movement of boom arm member 112 relative to boom base member 111 is powered by hydraulic cylinder 130. Hydraulic cylinder 130 is anchored at one end to boom base member 111; anchor bracket 131 is pinned to anchor plate 132 by means of suitable anchor pin 133. Hydraulic cylinder 130 further includes piston rod 134. One end of piston rod 134 is anchored to boom arm member 112 with anchor pin 135. Piston rod 134 can be extended and retracted with respect to hydraulic cylinder 130, thereby permitting boom arm member 112 to swing about a horizontal axis passing through boom pivot joint 113.

[0055] Pipe gripper assembly 200 is mounted at the outer extent of boom arm member 112. Pipe gripper assembly 200 includes opposing arcuate jaws 201 a and 201 b. Pipe gripper assembly 200 is mounted to mounting plate 208, which is in turn pivotably mounted to the end of boom arm member 112 with pivot pin 202, thereby permitting said pipe gripper assembly 200 to pivot about a horizontal axis passing through said pivot pin 202.

[0056] Pivoting of said pipe gripper assembly 200 about said horizontal axis passing through pivot pin 202 is powered by hydraulic cylinder 203. One end of hydraulic cylinder 203 is anchored to boom arm member 112 using anchor bracket 204 and anchor pin 205. Hydraulic cylinder 203 further includes piston rod 206. The outer end of piston rod 206 is pinned to mounting plate 208 using anchor pin 207. As piston rod 206 of hydraulic cylinder 203 extends and retracts, pipe gripper assembly 200 can swivel about pivot pin 202, and can tilt up or down about a horizontal axis passing through pivot pin 202, as desired.

[0057] Derrick control panel subassembly 300 includes a bank of valves which are electrically opened and closed using controls 301. Further, said valves are shiftable to provide hydraulic power fluid to a selected one or more of the hydraulic cylinders used to power jointed articulating boom 110 and pipe gripper assembly 200 as may be required during the operation of the apparatus for stabbing and positioning a section of casing. Derrick control panel subassembly 300 is in close proximity to jointed articulating boom 110, and is used primarily to manipulate and/or position jointed articulating boom 110 while said assembly is being mounted to, or removed from, derrick 11.

[0058] Hydraulic power fluid supply conduits 136 extend from one end of each of the valves downwardly to the drilling platform and are there connected to a suitable hydraulic pump (not shown in FIG. 2) for the purpose of supplying hydraulic power fluid necessary to operate the several hydraulic cylinder and piston assemblies hereinbefore described. Return conduits 137 also project from each of the valves to the drilling platform to allow exhausted hydraulic fluid to return to a reservoir or sump in the course of recirculation in a conventional fashion.

[0059] In its standard configuration, a remote control panel subassembly is used to control the movement of jointed articulating boom 110 and pipe gripper assembly 200. Referring to FIG. 1, said remote control panel subassembly 400 is depicted as being positioned on rig floor 12. Remote control panel 400 includes a bank of electrically actuated valves and valve controls 401 similar to derrick control panel subassembly 300. Hydraulic power fluid supply conduits 136 and 137 extend out of derrick 11 to pump 402. Operator 403 operates pipe stabbing apparatus 100.

[0060] In order to shift valves controlled by valve controls 401, electrical solenoids are included in remote control panel subassembly 400, and are actuated by power signals delivered via conductors extended through a control cable 404 which extends from the drilling platform upwardly to the remote control panel subassembly 400. Said control cable can be plugged into remote control panel subassembly 400 using a suitable jack.

[0061]FIG. 3 depicts a perspective view of pipe gripper assembly 200 of the present invention in the substantially open position. Pipe gripper 200 is comprised of opposing arcuate jaws 201 a and 201 b. Said opposing arcuate jaws 201 a and 201 b are pivotably attached to back member 210 using pivot pins 211 a and 211 b, and can swing to permit opening and closing of pipe gripper assembly 200. In the preferred embodiment, opposing arcuate jaws 201 a and 201 b operate in synchronized fashion, such that said opposing arcuate jaws open and close together.

[0062] Hydraulic cylinder 212 powers the synchronized opening and closing of opposing arcuate jaws 201 a and 201 b. Hydraulic cylinder 212 has piston rod 213, which can be extended and retracted. One end of hydraulic cylinder 212 is anchored to extension fingers 214 using anchor bolt 215. Similarly, the outer end of piston rod 213 is anchored to extension fingers 216 using anchor bolt 217. By actuating hydraulic cylinder 212, and thereby extending or retracting piston rod 213, opposing arcuate jaws 201 a and 201 b can pivot about pivot pins 211 a and 211 b, respectively. Mounting bracket 218 is attached to back member 210, and facilitates mounting of pipe gripper assembly 200 to mounting plate 208 (not shown in FIG. 3).

[0063]FIG. 4 depicts a perspective view of pipe gripper assembly 200 in a substantially closed position. Opposing arcuate jaws 201 a and 201 b are depicted as gripping a section of cylindrical pipe, such as a joint of large diameter casing, around the outer peripheral surface of said pipe. For purposes of illustration, said cylindrical pipe could be identical to casing section 18. As piston rod 213 extends relative to hydraulic cylinder 212, opposing arcuate jaws 201 a and 201 b close together in synchronized manner and grip around the outer peripheral surface of casing section 18.

[0064]FIG. 5 depicts a systemic view of the pipe stabbing apparatus 100 of the present invention. Pipe stabbing apparatus 100 includes jointed articulating boom 110; said boom is comprised of boom base member 111 and boom arm member 112, which are pivotably joined with boom pivot joint 113. In the preferred embodiment, said articulating boom is comprised of two structural members, with a single joint between said two structural members. Also in the preferred embodiment, boom base member is formed with obtuse angle 111 a, while arm member 112 is substantially straight.

[0065] Boom base member 111 is pivotably attached to eccentric base plate 119, which is in turn pivotably anchored to vertical base shaft 115. Eccentric base plate 119 pivots about pivot pin 116, thereby permitting boom base member 111, and ultimately all of jointed articulating boom 110, to rotate about a vertical axis passing through said vertical base shaft 115 and pivot pin 116.

[0066] Rotation of boom base member 110 about pivot pin 116 is powered by hydraulic cylinder 117. One end of hydraulic cylinder 117 is anchored to mounting assembly 114 with anchor means 118, such as a suitable pin. Hydraulic cylinder 117 further includes piston rod 120; the outer end of piston rod 120 is in turn pinned to eccentric plate 119. As piston rod 120 of hydraulic cylinder 117 is extended and retracted, eccentric plate 119 rotates about pivot pin 116 which in turn causes boom base member 111 (and, ultimately, all of jointed articulating boom 110) to rotate about a vertical axis passing through and parallel to said pivot pin 116.

[0067] Jointed articulating boom 110 extends and retracts by cooperative motion between boom base member 111 and boom arm member 112. Boom base member 111 is pivotably mounted to eccentric plate 119 using pivot pin 121. As a result, boom base member 111 can pivot about a horizontal axis passing through said pivot pin 121, thereby permitting boom base member 111 to tilt or lean forward and backward into an upright position.

[0068] Tilting of boom base member 111 is powered by hydraulic cylinder 122. Hydraulic cylinder 122 is anchored to vertical base shaft 115. Anchor bracket 123 is pinned to anchor plate 124 by means of a suitable anchor pin 125. Hydraulic cylinder 122 further includes piston rod 126, which can be extended and retracted with respect to hydraulic cylinder 122. Piston rod 126 is anchored to clevis plate 127 using clevis bracket 128 and clevis pin 129.

[0069] Similarly, movement of boom arm member 112 relative to boom base member 111 is powered by hydraulic cylinder 130. Hydraulic cylinder 130 is anchored at one end to boom base member 111. Anchor bracket 131 is pinned to anchor plate 132 by means of suitable anchor pin 133. Hydraulic cylinder 130 further includes piston rod 134, which is anchored to boom arm member 112 with anchor pin 135. Piston rod 134 can be extended and retracted with respect to hydraulic cylinder 130, thereby permitting boom arm member 112 to swing by pivoting about boom pivot joint 113.

[0070] Pipe gripper 200 is mounted at the outer extent of boom arm member 112. Pipe gripper 200 is comprised of opposing arcuate jaws 201 a and 201 b. Pipe gripper 200 is pivotably mounted to the end of boom arm member 112 with pivot pin 202, thereby permitting said pipe gripper to pivot about a horizontal axis passing through said pivot pin 202.

[0071] Pipe gripper 200 can pivot about said horizontal axis passing through pivot pin 202, and is powered by hydraulic cylinder 203. One end of hydraulic cylinder 203 is anchored to boom arm member 112 with anchor bracket 204 and anchor pin 205. Hydraulic cylinder 203 further includes piston rod 206, which is in turn pinned to mounting plate 208 using anchor pin 207. As piston rod 206 of hydraulic cylinder 203 extends or retracts, pipe gripper 200 can pivot about pivot pin 202 and can tilt about a horizontal axis passing through pivot pin 202.

[0072] Hydraulic power fluid supply conduits 136 extend from one end of each of the valves downwardly to the drilling platform and is there connected to a suitable hydraulic pump for the purpose of supplying the hydraulic power fluid necessary to operate the several hydraulic cylinder and piston assemblies hereinbefore described. Return conduits 137 also project from each of the valves downwardly to the drilling platform to allow exhausted hydraulic fluid to return to a reservoir or sump in the course of recirculation in a conventional fashion.

[0073] In its standard configuration, a remote control panel subassembly is used to control the movement of jointed articulating boom 110 and pipe gripper 200. In order to shift valves 401, electrical solenoids are included in remote control panel subassembly 400, and are actuated by power signals delivered via conductors extended through a control cable 404 which extends from the drilling platform upwardly to the remote control panel subassembly 400. Said control cable can be plugged into remote control panel subassembly 400 using a suitable jack.

[0074]FIG. 6 is a perspective view of the pipe gripping jaws of the present invention, in the closed position, gripping a section of large diameter casing. FIG. 7 is a side view of the pipe gripping jaws of the present invention, in the closed position, gripping a section of large diameter casing.

[0075] In operation, the casing stabbing apparatus 110 of the invention will be mounted at some intermediate location within derrick 11, such as on a cross member thereof as illustrated in FIG. 1, using mounting assembly 114. With the casing stabbing apparatus 110 thus mounted and positioned within derrick 11, the various hydraulic piston and cylinder assemblies are then used to engage upper casing section 18 hung from upper slips 19 on traveling block 20.

[0076] The opposing arcuate jaws 201 a and 201 b are opened apart from each other by pivotation of each of the jaws about the respective pivot pins 211 a and 211 b. With the arcuate casing jaws 201 a and 201 b thus opened apart from each other, said jaws are then moved to a position where they surround the suspended upper casing section 18. This is accomplished by means of the piston and cylinder subassembly previously described.

[0077] When upper casing section 18 has been thus engaged by opposing arcuate jaws 201 a and 201 b, operator 403, by appropriate manipulation of the control valves on remote control assembly 400, can cause casing section 18 to be moved in small increments in any direction. Thus, by remote control, operator 403 can move casing section 18 to a position directly above lower casing section 17 held by lower slips 16 in rotary 14. Then, as traveling block 20 is lowered, the threads at the lower end of suspended upper casing section 18 can be made to precisely align with the mating threads in lower casing section 17 in the vicinity of the rotary table. Suspended upper casing section 18 can be rotated to tighten such mating threads into engagement with each other without damage to said threads, and with a minimum amount of manual manipulation required by personnel on the rig floor. Importantly, the dangerous procedure of having a crew member manually manipulating the heavy casing section from a position high in the derrick is totally eliminated. With the present invention it is not even necessary for the operator of the hydraulically powered casing stabbing apparatus to be in the derrick. When upper casing section 18 has been joined with lower casing section 17, opposing arcuate jaws 201 a and 201 b are opened apart from each other.

[0078] In many instances, it will be desired, at times when the casing stabbing apparatus 100 is not in use, to move jointed articulating boom 110 to a position where it does not project out over the rig floor 12, and does not interfere with other pipe or tubular member handling operations.

[0079] The pipe stabbing apparatus of the invention is particularly efficient and effective in use because it eliminates the need to have one and frequently two persons in the rig derrick who try to manipulate the casing manually, or even to control the hydraulically controlled apparatus of this invention. With the present invention, this control can be entirely from a remote location, such as the rig floor. By the use of the remote control assembly 400, operator 403 can set up at the optimum location. As such, operator 403 can detect the direction of lean, if any, of the suspended elongated casing section.

[0080] Although the pipe stabbing apparatus of the present invention has been depicted in a particular form constituting a preferred embodiment, it will be understood that various changes and modifications in the illustrated and described structure can be effected without departure from the basic principles which underlie the invention. Changes and innovations of this type are deemed to be circumscribed by the spirit and scope of the invention except as such spirit and scope may be necessarily limited by the appended claims, or reasonable equivalents thereof. 

What is claimed is:
 1. An apparatus for positioning and stabbing pipe in a drilling rig derrick comprising: a. a support base attached to a structural member of a drilling rig derrick; b. a boom base member having a first end and a second end, wherein said first end is pivotally attached to said support base and is rotatable about vertical and horizontal axes; c. a boom arm member having a first end and a second end, wherein said first end is pivotally attached to the second end of said boom base member; d. a pipe gripper attached to the second end of said boom arm member; and e. means for selectively positioning said boom base and boom arm members. 